U.S. Pat. No. 5,899,880 granted to Bellhouse et al. on May 4, 1999 and U.S. Pat. No. 5,865,796 (McCabe) issued on Feb. 2, 1999 relate to devices for the high velocity injection of medicinal powders through the skin or other target tissue of a patient by means of high pressure gas.
More specifically, U.S. Pat. No. 5,899,880 describes a needeless syringe capable of accelerating the medicine to speeds sufficient to obtain the desired therapeutic effect. A company, Powderject Research Limited in the United Kingdom and Powderject Vaccines, Inc. in the United States, has been founded to exploit that concept.
U.S. Pat. No. 5,865,796 describes an essentially similar device, developed for the benefit of the same company. This device is destined to a usage in laboratory, for injecting genetic material.
The two above devices are designed for use with a medicine under the form of powder. They accelerate an inert gas by means of a supersonic gas flow.
The following companies already commercialize needleless syringes:                Powderject (www.powderject.com) uses a supersonic gaseous flow to accelerate microscopic particles in order to inject these particles into the skin or other target tissue of a subject;        Bioject (www.bioject.com) uses a micro-jet of high pressure liquid for the needleless penetration of the skin or other target tissue of a subject;        Advantajet (www.advantajet.com) uses a micro-jet of low pressure liquid, this system being optimized for insulin;        Mediject (www.mediject.com) uses an insulin injection system similar to that of Advantajet; and        Many other companies exploit the concept of high pressure liquid jet for the needleless injection of liquids.        